Evaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones

Yu Yan; Yubin Lan; Guobin Wang; Mujahid Hussain; Huizheng Wang; Xiaoqing Yu; Changfeng Shan; Baoju Wang; Cancan Song

doi:10.3389/fpls.2023.1303669

Evaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones

Front Plant Sci. 2023 Nov 29:14:1303669. doi: 10.3389/fpls.2023.1303669. eCollection 2023.

Authors

Yu Yan^{1

2}, Yubin Lan^{1

2}, Guobin Wang^{1

2}, Mujahid Hussain^{1

2}, Huizheng Wang^{1

2}, Xiaoqing Yu³, Changfeng Shan^{1

2}, Baoju Wang^{1

2}, Cancan Song^{1

2}

Affiliations

¹ College of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, China.
² Shandong University of Technology Sub-center, National Center for International Collaboration Research on Precision Agricultural Aviation, Zibo, China.
³ Plant Protection Station of Shandong Province, Jinan, China.

Abstract

Plant protection drone spraying technology is widely used to prevent and control crop diseases and pests due to its advantages of being unaffected by crop growth patterns and terrain restrictions, high operational efficiency, and low labor requirements. The operational parameters of plant protection drones significantly impact the distribution of spray droplets, thereby affecting pesticide utilization. In this study, a field experiment was conducted to determine the working modes of two representative plant protection drones and an electric backpack sprayer as a control to explore the characteristics of droplet deposition with different spray volumes in the citrus canopy. The results showed that the spraying volume significantly affected the number of droplets and the spray coverage. The number of droplets and the spray coverage area on the leaf surface were significantly increased by increasing the spray volume from 60 L/ha to 120 L/ha in plant protection drones. Particularly for the DJI T30, the mid-lower canopy showed a spray coverage increase of 52.5%. The droplet density demonstrated the most significant variations in the lower inner canopy, ranging from 18.7 droplets/cm² to 41.7 droplets/cm² by XAG V40. From the deposition distribution on fruit trees, the plant protection drones exhibit good penetration ability, as the droplets can achieve a relatively even distribution in different canopy layers of citrus trees. The droplet distribution uniformity inside the canopy is similar for XAG V40 and DJI T30, with a variation coefficient of approximately 50%-100%. Compared to the plant protection drones, the knapsack electric sprayer is suitable for pest and disease control in the mid-lower canopy, but they face challenges of insufficient deposition capability in the upper canopy and overall poor spray uniformity. The distribution of deposition determined in this study provides data support for the selection of spraying agents for fruit trees by plant protection drones and for the control of different pests and diseases.

Keywords: application volume; citrus; number of droplets; plant protection drones; spray coverage.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Top Talents Program for One Case One Discussion of Shandong Province and Shandong Province Natural Science Foundation (ZR2021QC154).